include/net/inet_connection_sock.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * NET          Generic infrastructure for INET connection oriented protocols.
   4  *
   5  *              Definitions for inet_connection_sock
   6  *
   7  * Authors:     Many people, see the TCP sources
   8  *
   9  *              From code originally in TCP
  10  */
  11 #ifndef _INET_CONNECTION_SOCK_H
  12 #define _INET_CONNECTION_SOCK_H
  13
  14 #include <linux/compiler.h>
  15 #include <linux/string.h>
  16 #include <linux/timer.h>
  17 #include <linux/poll.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sockptr.h>
  20
  21 #include <net/inet_sock.h>
  22 #include <net/request_sock.h>
  23
  24 /* Cancel timers, when they are not required. */
  25 #undef INET_CSK_CLEAR_TIMERS
  26
  27 struct inet_bind_bucket;
  28 struct tcp_congestion_ops;
  29
  30 /*
  31  * Pointers to address related TCP functions
  32  * (i.e. things that depend on the address family)
  33  */
  34 struct inet_connection_sock_af_ops {
  35         int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
  36         void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  37         int         (*rebuild_header)(struct sock *sk);
  38         void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  39         int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  40         struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
  41                                       struct request_sock *req,
  42                                       struct dst_entry *dst,
  43                                       struct request_sock *req_unhash,
  44                                       bool *own_req);
  45         u16         net_header_len;
  46         u16         net_frag_header_len;
  47         u16         sockaddr_len;
  48         int         (*setsockopt)(struct sock *sk, int level, int optname,
  49                                   sockptr_t optval, unsigned int optlen);
  50         int         (*getsockopt)(struct sock *sk, int level, int optname,
  51                                   char __user *optval, int __user *optlen);
  52         void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
  53         void        (*mtu_reduced)(struct sock *sk);
  54 };
  55
  56 /** inet_connection_sock - INET connection oriented sock
  57  *
  58  * @icsk_accept_queue:     FIFO of established children
  59  * @icsk_bind_hash:        Bind node
  60  * @icsk_timeout:          Timeout
  61  * @icsk_retransmit_timer: Resend (no ack)
  62  * @icsk_rto:              Retransmit timeout
  63  * @icsk_pmtu_cookie       Last pmtu seen by socket
  64  * @icsk_ca_ops            Pluggable congestion control hook
  65  * @icsk_af_ops            Operations which are AF_INET{4,6} specific
  66  * @icsk_ulp_ops           Pluggable ULP control hook
  67  * @icsk_ulp_data          ULP private data
  68  * @icsk_clean_acked       Clean acked data hook
  69  * @icsk_listen_portaddr_node   hash to the portaddr listener hashtable
  70  * @icsk_ca_state:         Congestion control state
  71  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  72  * @icsk_pending:          Scheduled timer event
  73  * @icsk_backoff:          Backoff
  74  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  75  * @icsk_probes_out:       unanswered 0 window probes
  76  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  77  * @icsk_ack:              Delayed ACK control data
  78  * @icsk_mtup;             MTU probing control data
  79  */
  80 struct inet_connection_sock {
  81         /* inet_sock has to be the first member! */
  82         struct inet_sock          icsk_inet;
  83         struct request_sock_queue icsk_accept_queue;
  84         struct inet_bind_bucket   *icsk_bind_hash;
  85         unsigned long             icsk_timeout;
  86         struct timer_list         icsk_retransmit_timer;
  87         struct timer_list         icsk_delack_timer;
  88         __u32                     icsk_rto;
  89         __u32                     icsk_pmtu_cookie;
  90         const struct tcp_congestion_ops *icsk_ca_ops;
  91         const struct inet_connection_sock_af_ops *icsk_af_ops;
  92         const struct tcp_ulp_ops  *icsk_ulp_ops;
  93         void __rcu                *icsk_ulp_data;
  94         void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
  95         struct hlist_node         icsk_listen_portaddr_node;
  96         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
  97         __u8                      icsk_ca_state:6,
  98                                   icsk_ca_setsockopt:1,
  99                                   icsk_ca_dst_locked:1;
 100         __u8                      icsk_retransmits;
 101         __u8                      icsk_pending;
 102         __u8                      icsk_backoff;
 103         __u8                      icsk_syn_retries;
 104         __u8                      icsk_probes_out;
 105         __u16                     icsk_ext_hdr_len;
 106         struct {
 107                 __u8              pending;       /* ACK is pending                         */
 108                 __u8              quick;         /* Scheduled number of quick acks         */
 109                 __u8              pingpong;      /* The session is interactive             */
 110                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
 111                 __u32             ato;           /* Predicted tick of soft clock           */
 112                 unsigned long     timeout;       /* Currently scheduled timeout            */
 113                 __u32             lrcvtime;      /* timestamp of last received data packet */
 114                 __u16             last_seg_size; /* Size of last incoming segment          */
 115                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 116         } icsk_ack;
 117         struct {
 118                 int               enabled;
 119
 120                 /* Range of MTUs to search */
 121                 int               search_high;
 122                 int               search_low;
 123
 124                 /* Information on the current probe. */
 125                 int               probe_size;
 126
 127                 u32               probe_timestamp;
 128         } icsk_mtup;
 129         u32                       icsk_user_timeout;
 130
 131         u64                       icsk_ca_priv[104 / sizeof(u64)];
 132 #define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
 133 };
 134
 135 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 136 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 137 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 138 #define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
 139 #define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 140 #define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 141
 142 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 143 {
 144         return (struct inet_connection_sock *)sk;
 145 }
 146
 147 static inline void *inet_csk_ca(const struct sock *sk)
 148 {
 149         return (void *)inet_csk(sk)->icsk_ca_priv;
 150 }
 151
 152 struct sock *inet_csk_clone_lock(const struct sock *sk,
 153                                  const struct request_sock *req,
 154                                  const gfp_t priority);
 155
 156 enum inet_csk_ack_state_t {
 157         ICSK_ACK_SCHED  = 1,
 158         ICSK_ACK_TIMER  = 2,
 159         ICSK_ACK_PUSHED = 4,
 160         ICSK_ACK_PUSHED2 = 8,
 161         ICSK_ACK_NOW = 16       /* Send the next ACK immediately (once) */
 162 };
 163
 164 void inet_csk_init_xmit_timers(struct sock *sk,
 165                                void (*retransmit_handler)(struct timer_list *),
 166                                void (*delack_handler)(struct timer_list *),
 167                                void (*keepalive_handler)(struct timer_list *));
 168 void inet_csk_clear_xmit_timers(struct sock *sk);
 169
 170 static inline void inet_csk_schedule_ack(struct sock *sk)
 171 {
 172         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 173 }
 174
 175 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 176 {
 177         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 178 }
 179
 180 static inline void inet_csk_delack_init(struct sock *sk)
 181 {
 182         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 183 }
 184
 185 void inet_csk_delete_keepalive_timer(struct sock *sk);
 186 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 187
 188 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 189 {
 190         struct inet_connection_sock *icsk = inet_csk(sk);
 191
 192         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 193                 icsk->icsk_pending = 0;
 194 #ifdef INET_CSK_CLEAR_TIMERS
 195                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 196 #endif
 197         } else if (what == ICSK_TIME_DACK) {
 198                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 199 #ifdef INET_CSK_CLEAR_TIMERS
 200                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 201 #endif
 202         } else {
 203                 pr_debug("inet_csk BUG: unknown timer value\n");
 204         }
 205 }
 206
 207 /*
 208  *      Reset the retransmission timer
 209  */
 210 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 211                                              unsigned long when,
 212                                              const unsigned long max_when)
 213 {
 214         struct inet_connection_sock *icsk = inet_csk(sk);
 215
 216         if (when > max_when) {
 217                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 218                          sk, what, when, (void *)_THIS_IP_);
 219                 when = max_when;
 220         }
 221
 222         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 223             what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
 224             what == ICSK_TIME_REO_TIMEOUT) {
 225                 icsk->icsk_pending = what;
 226                 icsk->icsk_timeout = jiffies + when;
 227                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 228         } else if (what == ICSK_TIME_DACK) {
 229                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 230                 icsk->icsk_ack.timeout = jiffies + when;
 231                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 232         } else {
 233                 pr_debug("inet_csk BUG: unknown timer value\n");
 234         }
 235 }
 236
 237 static inline unsigned long
 238 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 239                      unsigned long max_when)
 240 {
 241         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 242
 243         return (unsigned long)min_t(u64, when, max_when);
 244 }
 245
 246 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
 247
 248 int inet_csk_get_port(struct sock *sk, unsigned short snum);
 249
 250 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 251                                      const struct request_sock *req);
 252 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 253                                             struct sock *newsk,
 254                                             const struct request_sock *req);
 255
 256 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 257                                       struct request_sock *req,
 258                                       struct sock *child);
 259 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 260                                    unsigned long timeout);
 261 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 262                                          struct request_sock *req,
 263                                          bool own_req);
 264
 265 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 266 {
 267         reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 268 }
 269
 270 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 271 {
 272         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 273 }
 274
 275 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 276 {
 277         return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
 278 }
 279
 280 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 281 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 282
 283 static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
 284 {
 285         /* The below has to be done to allow calling inet_csk_destroy_sock */
 286         sock_set_flag(sk, SOCK_DEAD);
 287         percpu_counter_inc(sk->sk_prot->orphan_count);
 288 }
 289
 290 void inet_csk_destroy_sock(struct sock *sk);
 291 void inet_csk_prepare_forced_close(struct sock *sk);
 292
 293 /*
 294  * LISTEN is a special case for poll..
 295  */
 296 static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
 297 {
 298         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 299                         (EPOLLIN | EPOLLRDNORM) : 0;
 300 }
 301
 302 int inet_csk_listen_start(struct sock *sk, int backlog);
 303 void inet_csk_listen_stop(struct sock *sk);
 304
 305 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 306
 307 /* update the fast reuse flag when adding a socket */
 308 void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
 309                                struct sock *sk);
 310
 311 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 312
 313 #define TCP_PINGPONG_THRESH     3
 314
 315 static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 316 {
 317         inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
 318 }
 319
 320 static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 321 {
 322         inet_csk(sk)->icsk_ack.pingpong = 0;
 323 }
 324
 325 static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 326 {
 327         return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 328 }
 329
 330 static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
 331 {
 332         struct inet_connection_sock *icsk = inet_csk(sk);
 333
 334         if (icsk->icsk_ack.pingpong < U8_MAX)
 335                 icsk->icsk_ack.pingpong++;
 336 }
 337
 338 static inline bool inet_csk_has_ulp(struct sock *sk)
 339 {
 340         return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
 341 }
 342
 343 #endif /* _INET_CONNECTION_SOCK_H */